The purpose of the proposed research program will be to continue to study the naturally occurring diseases of laboratory animals which occur in the colonies of the University of Rochester School of Medicine including its several Associated Hospitals and two non-University research colonies as well. Studies will be conducted by well-established clinical, clinical pathologic, anatomic pathologic, and microbiologic techniques developed and used in the Animal Disease Diagnostic Laboratory over the past eight years, the last five of which having been supported by the P.H.S. Such studies will continue to enable us to (1) identify and characterize disease in the colonies, (2) make sound decisions relative to appropriate methods of prophylaxis and therapy, (3) consult with research investigators on intercurrent disease problems, (4) accumulate teaching materials for our pre-doctoral and post-doctoral teaching programs, (5) expand our base in our data storage and retrieval system and (6) afford us the opportunity to discover and characterize new or improved animal models which may be useful in research. The support requested for this project is considerably lower than in previous years since the school is committed to eventually totally supporting these activities through intramural means. This goal should be achieved at the end of the requested 3 year support period.